The invention relates to a sterilized liquid or semi-solid acid enteral composition comprising per 100 ml 9 to 20 g of non-hydrolyzed globular proteins, fat and at least 100 mg of divalent metal cations and having a pH ranging between 3 and 5. The invention further relates to a method for preparing a composition according to the invention, comprising a step wherein at least the non-hydrolyzed globular proteins are subjected to a direct steam injection (DSI) at specific holding values, such as a holding temperature of 100 to 140° C. during a holding time of about 0.5 to 10 seconds, followed by a homogenization step and a sterilization step The composition according to the invention has a reduced astringency and can be used for medical purposes, such as for stimulating muscle protein synthesis in a mammal, in particular for treating sarcopenia, and for specific groups of people, such as elderly and sportsman.